import pygame

class Myball():
    def __init__(self, ai_settings, screen):
        
        self.screen = screen
        self.ai_settings = ai_settings
        self.image = pygame.image.load("C:/Users/DP/AppData/Local/Programs/Python/Python37/images/life.png").convert_alpha()
        self.rect = self.image.get_rect()
        self.screen_rect = screen.get_rect()
        #将每艘飞船放在屏幕底部中央
        self.rect.centerx = self.screen_rect.centerx  
        self.rect.bottom = self.screen_rect.bottom
        #移动标志
        self.center = float(self.rect.centerx)
        
        self.moving_right = False
        self.moving_left = False

    def update(self):

        if self.moving_right and self.rect.right < self.screen_rect.right:
            self.center += self.ai_settings.ship_speed_factor
        if self.moving_left and self.rect.left > 0:
            self.center -= self.ai_settings.ship_speed_factor
        self.rect.centerx = self.center          
    def blitme(self):

        self.screen.blit(self.image,self.rect)

    def center_ship(self):
        self.center = self.screen_rect.centerx

